Question: A goblet contains $3$ red balls, $4$ green balls, and $11$ blue balls. If a ball is randomly chosen, what is the probability that it is not red?
Explanation: There are $3 + 4 + 11 = 18$ balls in the goblet. There are $3$ red balls. That means $18 - 3 = 15$ are not red. The probability is $ \frac{15}{18} = \dfrac{5}{6}$.